The 'Harry Potter' star - who first joined forces with the ethical clothing company when she designed a collection for them last year - revealed the line has expanded and now includes dresses, skirts and shirts made from hand-woven Fair Trade brushed fabric.

She explained: "Although I wasn't centrally involved in the design of this collection, I had great fun in helping People Tree select some gorgeous Fair Trade textiles, such as a dogtooth hand-woven check, cable knits, and the first Fair Trade hand-woven brushed checked fabric, which has been made into easy tulip skirts, dresses and shirts.

"There are even a few party dresses, such as the little black satin tulip dress which can be dressed up or down to suit any occasion."

The 20-year-old beauty - who has also fronted Burberry campaigns in the past - admitted she found visiting garment factories in Dhaka, Bangladesh, an "upsetting" experience.

She said: "I had some preconceived ideas but nothing prepared me for the reality. It was upsetting to see the conditions in which these people live, but I was incredibly moved by their spirit and friendliness in spite of such apparent adversity.

"Having seen the slums in Dhaka and the conditions in which these people live and work to produce 'fast fashion', I would say to those people that this is not the way we should be making clothes in The Modern world."